Fancybox auto width/height nightmare

On our internal ticket system we have a two different "pop-out" boxes for displaying information about a specific ticket. Any way, both of these have different widths but consistent heights so in the fancybox.js I have created a max-width/height and set autosize to true, which in my mind should solve my issue. However things are never that simple, for some reason fancybox will always set the width to 342px which is fine for the smaller box but ruins the readability of the larger. Anyone have a similar experience? And how did you get past it?

Thanks